It is general, in the past, to construct a player of an optical disk such as CD, MD or LD, etc., such that a tray on which the optical disk is mounted is transported to a spindle position in the player. The spindle rotates the optical disk through the tray to perform a data read operation. In reading data recorded on the optical disk, operations with respect to the disk set in a read position, including focusing of a laser light onto a surface of the optical disk, tracking the optical disk with an optical head and shifting of the optical head radially of the disk, etc., are usually performed by controlling various drive motors and voice coil motors.
Therefore, a number of motors and a number of drivers for driving these motors are included in the device.
As an example, conventional drivers for a CD player are shown in FIG. 4. In FIG. 4, two driver ICs, that is, a power operational amplifier IC1 including spindle motor drivers D0a and D0b for rotating the optical disk and a power operational amplifier IC2 including four pairs of BTL (balanced transformer-less) divers D1a and D1b, D2a and D2b, D3a and D3b and D4a and D4b are provided. Reference numerals 3, 4, 5 and 6 depict current drive signal generator circuits each of which responds to an input drive signal to generate a current drive signal having phase different from the input drive signal by 180.degree. and sends them to a corresponding BTL driver set.
The BTL drivers D1a and D1b drive a tray motor M1 for moving the tray, the BTL drivers D2a and D2b drive a head shifting motor M2, the BTL drivers D3a and D3b drive a head tracking voice coil motor M3 and the BTL drivers D4a and D4b drive a focusing voice coil motor M4. The BTL drivers in each set operate in opposite phase to each other and the motors M, M1 and M2 are usually DC motors or single phase brushless motors.
As to an optical disk player for such as CD or MD, miniaturization thereof is required since it is incorporated in a micro component stereo device or is used as a portable device. Further, as to a drive device for optical disk such as CD-ROM, etc., miniaturization thereof is also required so that it can be used as a peripheral device of a personal computer of notebook type. Therefore, there is a requirement of constructing such driver circuit as a single chip IC. However, since size of a driver circuit tends to be increased with new functions to be given to the drive device, it becomes difficult to make it as one chip IC.